1. Field of the Invention
The present invention relates to A method of identifying a boundary condition between components of an object of analysis, particularly relates to the method of identifying the boundary condition between components, which replaces the object of analysis such as a structure or a mechanism with a finite-element method model for vibrational analysis or motion analysis and identifies the boundary condition between the components in the finite-element method model based on reference data obtained by an experiment.
2. Description of the Related Art
In Japanese Patent Application Laid-Open (JP-A) No. 05-209805, there is described a method for changing an unknown parameter to identify the parameter of a spring-particle system while comparing a natural frequency obtained by the experiment to the natural frequency determined by calculation as the identification method for the parameter of the spring-particle system.
However, in the above-described related art, a shape, a configuration, topology of a structure, and the like are not preserved because the object of analysis is replaced with a particle system. Therefore, there is a problem that a detail mode can not be used for the identification because information of the mode including the information of the shape, the configuration and the topology is lacked, besides not performing precise analysis up to a high frequency.
Further, because the above-described related art is based on a dynamic system such as the spring-particle system, there is the problem that it is difficult to expand the related art to a system having multi-degree of freedom or a discrete model of the structure such that a dynamical equation of the system can not be explicitly expressed and it is difficult to apply an actual problem.
When an error is mixed into the data used in formulating the dynamical equation of the system and identifying the system by adopting a least squares method or the like, sometimes there is caused such physical contradiction that the spring or mass becomes negative. In the method making a search for a value minimizing difference between an experimental result and a calculated result while an identification constant is gradually changed, there is a tendency to fall into a local solution at which arrives by using only specific variables having high sensitivity, so that sometimes there is the case in which an correct identification value is not obtained.
In JP-A No. 06-290225, there is described the method for expressing fuzziness of constraint and an objective in fuzzy (membership function) to design automobile components by utilizing an experimental design. In JP-A No. 10-207926, there is described a design-support method of the structure or the like, which utilizes the experimental design and response surface methodology for making an impact analysis/design equation of a plate thickness in buckling or crushing.
In JP-A No. 2001-117952, there is described an optimal design system which adopts the experimental design and the response surface methodology and utilizes a building block approach to make an input-format database suitable for the building block approach. In JP-A No. 10-301979, there is described a parameter extracting method of a model for simulation of a process, a device, and a circuit of a semiconductor integrated circuit, which extracts the parameter having the high sensitivity by utilizing the experimental method and discriminate between good and bad range setting to automatically reset the range.
In JP-A No. 11-281522, there is described an analytic method of vibrational characteristics which makes the equation from the natural frequency obtained by the experiment and the shape of a natural mode and determines a mass matrix [M] and a stiffness matrix [K], which become a characteristic matrix by adopting the least square method. In this method, the characteristic matrix having the more degrees of freedom can be obtained from the small number of modes obtained in the experiment. However, that the characteristic matrix is a symmetric matrix and has no damping are conditions on expansion of the equation.